Pro sites working with WHMCS setting problem

I've tried to make both work together. But again, the configuration to integrate WHMCS plugin may not be as easy as it seems.

I have created a WHMCS and Pro sites , and I also follow the instruction to setting the product/services .

1) I want my clients can apply the site name and make a payment in WHMCS , when they're completed the payment and will guide them to log in their site on Pro site.

2) But may be im miss something ,although Im try to apply a new site in WHMCS ,but in my pro site admin ,I didn't see any new site create from WHMCS .

3) When my clients register at WHMCS is it using that WHMCS user name and password to log in to pro site ? If no how to send the password to clients ?

I really need your help ,because of this problem puzzled my around 2 weeks. Please help me.

Thank you